Mix garlic, onion, cream cheese, GruyFre cheese and half-and-half in 1 1/2-quart slow cooker.
Cover and cook on low heat setting 2 1/2 to 3 hours or until mixture is hot.
Stir in bacon, horseradish and parsley. Cover and cook on high heat setting about 15 minutes or until mixture is hot. Serve with bread cubes or crackers for dipping.